With increased penetration of renewable energy sources and energy storage, high gain DC/DC power electronic converters find increased applications in, for example, green energy systems. They can be used to interface low voltage sources like fuel cells, photovoltaic (also called PV or solar) panels, batteries, and the like with a high voltage (e.g., 400 V) bus in a DC microgrid system. These converters also find applications in different types of electronic equipment such as high-intensity-discharge (HID) lamps for automobile headlamps, servo-motor drives, X-ray power generators, computer periphery power supplies, and uninterruptible power supplies (UPS).
Conventional DC/DC converter topologies feature varying levels of integration between commonly used topologies, such as boost and flyback topologies, in order to provide a high-gain. However, each proposed topology is deficient in requiring at least one of the following: a large inductor ripple current due to a high duty cycle requirement, or a discontinuous current input.
To achieve high voltage gains, classical boost and buck-boost converters require large switch duty ratios. Large duty cycles result in high current stress in the boost switch. The maximum voltage gain that can be achieved is constrained by the parasitic resistive components in the circuit and the efficiency is drastically reduced for large duty ratios. There are diode reverse recovery problems because the diode conducts for a short period of time. Also the high current and output voltage along with large current ripples would further degrade the efficiency of the converter. Typically high frequency transformers or coupled inductors are used to achieve high voltage conversion ratios. The transformer design is complicated and the leakage inductances increase for achieving larger gains, as the design requires higher number of winding turns. Increased leakage inductance leads to voltage spikes across the switches and voltage clamping techniques are required to limit voltage stresses on the switches. Implementing these design features results in a more complicated design.
Therefore, there is a need for a high-gain DC/DC power electronic converter that is energy efficient and cost-effective without the limitations as described above and that benefits from a continuous input current.